1. Field of the Invention
The present invention relates to a production process for a colorant containing a silicon phthalocyanine compound and a copper phthalocyanine compound and a colorant composition containing the colorant produced by the above production process. Further, the present invention relates to an image recording material and a color filter prepared by using the above colorant composition.
2. Description of the Related Art
In recent years, particularly materials for forming color images are used mainly for an image recording material, and application fields of color compositions include, to be specific, ink jet recording materials, electrophotographic recording materials, recording materials of a thermal transfer system, optical recording media, transfer system silver halide photosensitive materials, printing inks, recording pens and the like. Also, color filters are used in order to record and reproduce color images in image sensors such as CCD and the like in a case of photographic equipments and in LCD and PDP in a case of displays. In the above color image recording materials and color filters, dyes of so-called three primary colors in an additive color process and a subtractive color process are used in order to reproduce or record full color images. However, solid dyes which have absorption characteristics capable of reproducing preferred color regions and which can stand various use conditions and environmental conditions are desired in the dyes of the three primary colors described above.
An image-forming method by an electrophotographic system has come to be used widely not only in conventional copying and printout of business documents but also in the field of on-demand printing. Output images themselves are products in the above light printing areas, and therefore the high image quality is naturally required.
In an image-forming method by an electrophotographic system, toners containing copper phthalocyanine compounds have so far been used principally as a cyan toner. However, the above toners have involved the problem that images which are output by using the cyan, toner alone or using it in combination with toners of other colors such as yellow (Y), magenta (M), black (K) and the like have a narrower color gamut than those of displays and that they are low particularly in a saturation.
In recent years, it has become clear that silicon phthalocyanine compounds are effectively used as a colorant for toners which have solved the above problems (refer to, for example, JP-A 2008-176311 and 2009-139933). However, it has been found that single use of the toners prepared by using the silicon phthalocyanine compounds as the colorant provides the vivid tones with an improved color reproducibility but the dark tones with an inferior color reproducibility
Accordingly, there has been proposed a technique in which from the viewpoint of improving the color reproducibility, a specific silicon phthalocyanine compound and a copper phthalocyanine compound are caused to be coexistent in a specific proportion and dispersed to produce a toner, whereby they are acted complementarily to obtain the high color reproducibility in a broad color gamut of a vivid tone to a dark tone (refer to, for example, JP-A 2009-128750).
Further, it has become possible to form toner images having both of a color reproducibility and a light fastness by using a toner which contains a silicon phthalocyanine compound as a colorant having a number average primary particle diameter of 30 nm or more and 200 nm or less and which has a number average particle diameter larger by 1.2 to 2.5 times than a number average primary particle diameter of the colorant in a state in which the colorant is contained in the toner particles (refer to, for example, JP-A 2010-19891).
On the other hand, it has become apparent that toners prepared by using silicon phthalocyanine as a colorant bring about the problem that dispersion in distribution of an electrostatic property in the toner causes the toner to scatter in a form of very fine powder in developing to stain an inside of the image forming equipment. Accordingly, toners containing silicon phthalocyanine compounds are mixed with toners containing copper phthalocyanine compounds in a specific proportion, whereby distribution of an electrostatic property in the toner particles in the whole part of the toner is uniformized, and stain in an inside of the equipment caused by scattering of the toners in developing has been solved (refer to, for example, JP-A 2011-85687).
An ink jet recording method is a printing method in which small droplets of an ink composition are blown and attached onto a recording medium such as paper and the like to carry out printing. The colors of the images obtained are reproduced by ink compositions of three colors which are divided roughly into cyan, magenta and yellow.
Phthalocyanine dyes are widely used for a cyan ink composition at present since they are high in a chromaticity, a light fastness and a heat resistance, and particularly Direct Blue 199 is widely used as a dye for a cyan ink for ink jet printing. Direct Blue 199 has an excellent light fastness and an excellent heat resistance, but it has the defects that it has a high absorption in magenta color region in a reflection spectrum of images and is unsatisfactory in a color reproducibility and that it has no resistance against oxidizing substances such as nitrogen oxides (NOx) and the like in the atmosphere and is faded for a short time.
On the other hand, a high transparency is required to color filters, and a high light fastness is required as well thereto in order to prevent fading and discoloring which are caused by light coming from backlights. Color filters have so far been colored by a method called a dyeing method in which they are colored with dyes, but the heat resistance and the light fastness have been unsatisfactory even by using phthalocyanine dyes which are excellent in a light fastness and a heat resistance. Also, it is known that even pigments which are considered to be excellent in a light fastness and a heat resistance are deteriorated in a light fastness by pulverizing into fine particles, and they have to be improved in a light fastness while maintaining the characteristics of a high transparency and a high color purity.
Accordingly, inks for ink jet and color filters which are prepared by using silicon phthalocyanine and which are excellent in all of a hue, a heat resistance and a light fastness are proposed (refer to, for example, JP-A 2009-126960).
On the other hand, a large number of technologies for developing the characteristics which are different from the absorption characteristics of original compounds by a solid solution (or mixed crystal) technology in which plural compounds are mixed in a molecular state has so far been known in cases of azo pigments, quinacridone pigments, diketo-pyrrolopyrrole pigments and the like. Also in a case of phthalocyanine pigments, disclosed is a method in which the raw materials of copper phthalocyanine and aluminum phthalocyanine are mixed in the reaction to synthesize them, whereby bluish green mixed crystals making it possible to form sharp and transparent images are obtained (refer to, for example, JP-A 2001-89682).
In conventional techniques, however, the following problems are involved.
The problem that the color reproducibility is still unsatisfactorily improved is involved in the technique described in JP-A 2009-128750. Further, in the technique described in JP-A 2010-19891, the colorant has to be dispersed by using a medium which is as very fine as 50 to 300 nm. Accordingly, desired to be developed are silicon phthalocyanine compounds which make it possible to reach a targeted particle diameter only by a conventional method using a medium (a bead mill and the like) having a diameter of several ten to several hundred μm. Also, in the technique described in JP-A 2011-85687, the color reproducibility has to be further improved, and a countermeasure which makes it possible to cause the color reproducibility to be compatible with an electrostatic property of the toner particles is desired to be employed. Further, in the technique described in JP-A 2009-126960, if the colorant particles can be dispersed in a fine form as is the case with the toner, the high transparency is obtained while maintaining the heat resistance and the light fastness. However, long time is necessary for dispersing the particles of the colorant in a fine form, and therefore silicon phthalocyanine compounds which make it easy to reach a targeted particle diameter by a conventional dispersing method are desired to be developed. In addition, in the technique described in JP-A 2001-89682, there is a room for improving the performances of the image recording material such as a color reproducibility, a light fastness, an electrostatic property, a transparency and the like, and the performances are desired to be further improved. Incidentally, in the technique described in JP-A 2001-89682, it is characterized by using aluminum phthalocyanine, and compounds of metals other than aluminum, such as silicon compounds and the like are not assumed at all to be used.
The present invention has been made in light of the problems described above, and an object thereof is to provide a production process for a colorant which contains a silicon phthalocyanine compound making it possible to reach a targeted particle diameter even by a conventional dispersing method and which is excellent in performances such as a color reproducibility, a light fastness, an electrostatic property, a transparency and the like, and a colorant composition, a toner, an ink for ink jet recording and a color filter which are excellent in the above performances.
To achieve at least one of the above-mentioned objects, a production process reflecting one aspect of the present invention comprises:
1. A production process for a colorant containing a silicon phthalocyanine compound and a copper phthalocyanine compound, comprising a preparing step of reacting raw materials of a silicon compound and phthalocyanine under the presence of a copper salt or the copper phthalocyanine compound described above to prepare the silicon phthalocyanine compound described above.
2. The production process for a colorant as described in the above aspect 1, wherein the silicon phthalocyanine compound is represented by the following Formula (1):
[wherein Z represents a chlorine atom, a hydroxyl group, an alkyl group, an alkoxy group, an aryloxy group or a group represented by the following Formula (2); and A1 to A4 represent the following atomic groups (a-1) to (a-7) which may have substituents]:
[wherein R1 to R3 each represent independently an alkyl group, an aryl group or a siloxy group]:

3. The production process for a colorant as described in the above aspect 1 or 2, wherein the copper phthalocyanine compound is represented by the following Formula (3):
[wherein B1 to B4 have the same definitions as those of A1 to A4 in Formula (1)].
4. The production process for a colorant as described in any of the above aspects 1 to 3, comprising a preparing step of reacting the raw materials of the silicon compound and the phthalocyanine under the presence of the copper salt to prepare the silicon phthalocyanine compound.
5. The production process for a colorant as described in any of the above aspects 1 to 4, wherein the cooper salt is copper chloride.
6. The production process for a colorant as described in any of the above aspects 1 to 5, wherein a ration (m1:m2) of a mass content (m1) of the silicon phthalocyanine compound contained in the colorant to a mass content (m2) of the copper phthalocyanine compound contained in the colorant is 99:1 to 80:20.
7. A colorant composition comprising the colorant produced by the production process as described in any of the above aspects 1 to 6.
8. A toner comprising the colorant composition as described in the above aspect 7.
9. An ink for ink jet recording comprising the colorant composition as described in the above aspect 7.
10. A color filter comprising the colorant composition as described in the above aspect 7.